Cornwall Island measures about 90 km (56 mi) long and 30 km (19 mi) wide, and has an area of 2,358 km2 (910 sq mi).

The tallest peaks are McLeod Head at 400 m (1,300 ft), and Mount Nicolay at 290 m (950 ft), both on the north coast. Coast features include Northeast Point and Gordon Head to the east; Pell Point and Cape O'Brien to the south; and Cape Butler in the southwest.[1]

The first known sighting of the island was by Sir Edward Belcher on 30 August 1852 and was named in honour of Prince Edward, Prince of Wales and Duke of Cornwall.[2]